Originally Posted by Itsmeagain

Its an FSE power boost valve, ie an adjustable fuel pressure regulator that will replace the std one, just one that dont work properly Esp as the std cossie one is adjustable AND works properly anyhow

Top pipes the boost/vac pipe and will go to the inlet.
Side pipe will come from the fuel rail.
Bottom pipe is the return to the fuel tank.
Adjustable via the nut on top.